Johannes walter



UNITED STATES ATENT @rrrcnt JOHANNES WALTER, OF BASLE, SW ITZERLAND, ASSIGNOR TO JOHN R.

I GEIGY 8: 00., OF SAME PLACE.

PROCESS OF MAKING A YELLOW DYE.

SPECIFICATION forming part of Letters Patent No. 398,990, dated March 5, 1889.

Application filed December 18, 1888. Serial No. 293,995. (Specimens To all whom it may concern:

Be it known that I, Dr. J OHANNES WALTER, of Basle, Switzerland, have invented a certain new and useful Process for the Production of a Yellow Coloring-Matter, of which the following is a specification.

My invention relates to the manufacture of a yellow dye-stuff by the action of salicylic acid on diazothioparatoluidine sulphonic acid.

To carry out the invention, I dissolve, for instance, fifty kilos of the sodium salt of thioparatoluidine sulphonic acid in water and mix it with fifteen kilos of sulphuric acid. To the precipitate of the acid compound so obtained and cooled with ice six kilos of nitrite of sodium dissolved in water are gradually added. The solution of the diazo 00111- pound is poured into an alkaline solution of twelve kilos of salicylic acid containing enough caustic soda to saturate the whole quantity of acids employed. Two hours later the mixture is boiled, and then the color pre- 1 It can be used 1 cipitated with common salt.

for dyeing and printing cotton, and has the great advantage of standing both lightand chlorine.

Having; thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

he herein-described process for producing a new yellow coloring-matter by first dissolving sodium salt of thioparatoluidine sulphonic acid in water, mixingitwith sulphuric acid, and

to the precipitate of the acid compound thus obtained and cooled with ice adding gradually nitrite of sodium dissolved in water, the so- JOHAN NES WALTER.

Witnesses:

GEORGE GIFFoRD, (his. A. RICHTER. 

